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Variation in Appearance of Severe Zone 1 Retinopathy of Prematurity During Wide-angle Contact Photography
Susan Koreen, BS;
Robert Lopez, MD;
Danny H.-Kauffmann Jokl, MD;
John T. Flynn, MD;
Michael F. Chiang, MD
Arch Ophthalmol. 2008;126(5):736-737.
Retinopathy of prematurity (ROP) management presents significant challenges. The number of infants requiring surveillance is increasing, while the number of pediatric ophthalmologists or retinal specialists willing to perform examinations is decreasing because of medicolegal and reimbursement concerns.1 Although dilated examination by an experienced ophthalmologist is considered the standard of care, emerging technologies such as wide-angle retinal imaging and telemedicine have the potential to improve the accessibility, quality, and documentation of ophthalmic care for at-risk infants. Studies have shown that telemedical interpretation is highly accurate for detection of clinically significant ROP, including when digital images are captured by trained nonophthalmic personnel.2-3 This report illustrates a case in which wide-angle photography may misrepresent actual retinal findings.
Report of a Case
XW was a male infant born at gestational age 26 weeks and birth weight 764 g. Initial ophthalmoscopic examination was performed at 32 weeks' postmenstrual age and disclosed stage 3 ROP in zone 1 without plus disease. However, fundus images taken by an experienced photographer using a wide-angle camera (RetCam-II; Clarity Medical Systems, Pleasanton, California) immediately after ophthalmoscopy appeared to show only immature retinal vessels in zones 1 and 2 (Figure 1). When this discrepancy was noted, retinal photography was repeated with special attention to placing less pressure on the infant's eye from the camera. Findings consistent with the ophthalmoscopic examination were visualized in the second set of photographs, which were taken within 10 minutes of the initial images (Figure 2).
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Figure 1. Initial retinal imaging examination suggesting immature vascularization in zone 1.
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Figure 2. Second retinal imaging examination taken within 10 minutes of initial images, showing type 1 retinopathy of prematurity based on presence of stage 3 disease in zone 1. This was consistent with findings from the ophthalmoscopic examination.
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Despite bilateral laser photocoagulation for type 1 ROP, the retinal disease progressed to stage 4A detachment. Because of significant systemic comorbidities, the decision was made not to perform immediate surgical intervention. The infant died shortly afterward from respiratory failure and sepsis.
Comment
Results from the Early Treatment for ROP study support ablative therapy for eyes with type 1 ROP.4 When findings occur in zone 1, type 1 ROP is defined as any-stage ROP with plus disease or as stage 3 ROP without plus disease. These clinical examination findings would be expected to appear on a wide-angle posterior pole photograph. However, the initial images from this patient (Figure 1) appear to significantly underrepresent disease severity. Careful reevaluation of the initial images suggests the presence of vascular abnormalities. Although digital image processing with adjustment of brightness and contrast using software tools (Clarity Medical Systems) could somewhat improve visualization of peripheral ROP findings (Figure 3), we were unable to reproduce the exact appearance of abnormalities found in Figure 2 through this manipulation.
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Figure 3. Initial retinal image from Figure 1 after manual adjustment of brightness and contrast. This improved visualization of peripheral retinopathy of prematurity findings but could not reproduce exact appearance of abnormalities in Figure 2.
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We hypothesize that peripheral ROP findings were not obvious in the initial images because too much corneal force was applied during contact photography, resulting in increased intraocular pressure and interruption of retinal blood flow. Ophthalmodynamometry studies haveshown that an appositional force of 90g externally placed on the eye increases intraocular pressure to approximately 90 mm Hg, which is sufficient to overcome systolic pressures and cease central retinal artery blood flow.5 Given that even hard squeeze blinks have been shown to increase intraocular pressure in a range from 50 to 110 mm Hg,6 it is certainly conceivable that the appearance of peripheral ROP in this patient may have been altered through this mechanism.
Important advantages of wide-angle imaging for ROP include the opportunity for objective documentation of retinal structures, as well as serial comparison of findings. Using these images, telemedicine has the potential to improve the overall quality of ROP care through accessibility to experts and standardization of examination procedures. This report demonstrates that errors in image capture and interpretation can occur, even in severe posterior disease. Recognition of these cases, with adequate training of photographers and image graders, can improve the accuracy and reliability of wide-angle retinal imaging and telemedical ROPdiagnosis.
AUTHOR INFORMATION
Correspondence: Dr Chiang, Columbia University College of Physicians and Surgeons, 635 W 165th St, Box 92, New York, NY 10032 (chiang{at}dbmi.columbia.edu).
Author Contributions: Dr Chiang had full access to all the data in the study and takes responsibility for the integrity of the data and accuracy of the data analysis.
Financial Disclosure: Dr Chiang is an unpaid member of the Scientific Advisory Board of Clarity Medical Systems (Pleasanton, California).
Funding/Support: This work was supported by a Career Development Award from Research to Prevent Blindness, New York, New York (Dr Chiang), and by grant EY13972 from the National Eye Institute, Bethesda, Maryland (Dr Chiang).
Role of the Sponsor: The sponsors had no role in the design and conduct of the study; in the collection, analysis, and interpretation of data; or in the preparation, review, or approval of the manuscript.
REFERENCES
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1. American Academy of Ophthalmology. Ophthalmologists warn of shortage in specialists who treat premature babies with blinding eye condition. http://www.aao.org/newsroom/release/20060713.cfm. Accessed July 3, 2007.
2. Chiang MF, Keenan JD, Starren J; et al. Accuracy and reliability of remote retinopathy of prematurity diagnosis. Arch Ophthalmol. 2006;124(3):322-327.
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3. Chiang MF, Wang L, Busuioc M; et al. Telemedical retinopathy of prematurity diagnosis: accuracy, reliability, and image quality. Arch Ophthalmol. 2007;125(11):1531-1538.
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4. Early Treatment for Retinopathy of Prematurity Cooperative Group. Revised indications for the treatment of retinopathy of prematurity: results of the early treatment for retinopathy of prematurity randomized trial. Arch Ophthalmol. 2003;121(12):1684-1694.
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5. Entenmann B, Robert YC, Pirani P, Kanngiesser H, Dekker P. Contact lens tonometry—application in humans. Invest Ophthalmol Vis Sci. 1997;38(12):2447-2451.
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6. Miller D. Pressure of the lid on the eye. Arch Ophthalmol. 1967;78(3):328-330.
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